(css) Badge for mail folders unread count

UI/WebServerResources/scss/views/MailerUI.scss

@@ -11,6 +11,17 @@
   transform: translateY(-100%); // Compensate the container top-margin
 }
 
+.sg-unread-badge {
+  border-left-width: 1px;
+  border-left-color: #999;
+  border-style: solid;
+  margin: 0;
+  padding: 0 rem(0.500);
+  font-size: $sg-font-size-1;
+  font-weight: $sg-font-medium;
+  text-transform: uppercase;
+}
+
 .unread {
   .#{$md}-subhead-multi,
   .#{$md}-body-multi {